1. Field of the Invention
This invention relates to the production of diperazelaic acid from a fatty oil obtained from Helianthus annuus.
2. Statement of Related Art
The production of azelaic acid by oxidative ozonolysis of technical oleic acid is known from U.S. Pat. No. 2,450,858 and from U.S. Pat. No. 2,813,113. It is also known that diperazelaic acid can be produced by reaction of technical oleic acid with hydrogen peroxide in the presence of sulfuric acid, cf. D. Swern et al., J. Am, Chem. Soc., 79, 1929 et seq (1957); M. Dankowski, EP-A 127,782.
In the production of azelaic acid from technical oleic acid, it has been found that the presence of polyunsaturated fatty acids in the technical oleic acids used has an unfavorable effect due to the increased formation of secondary products. In addition, the technical oleic acid normally used is obtained by enrichment (solvent or hydrophilization processes) and purification of the oleic acid present in split tallow fatty acid. However, fundamental limits are imposed on the enrichment processes for recovering the oleic acid. Technically, therefore, 65 to 70% oleic acid is used in the production of azelaic acid.